Retrievable drill bit



5I- 5 T w Feb. 16, 1965 A. w. KAMMERER 3,169,592

RETRIEVABLE DRILL BIT Fj led Oct. 22. 1962 60 2. EGL

36 fllQCl/EE MKHMMEQER 4a 44 EYE INVENTOR.

United States Patent The present invention relates to subsurface well bore apparatus, and more particularly to apparatus for drilling I a well bore. by rotating a drilling string to which the apparatus is attached.

In the drilling of oil and gas wells underlying a body of water, it is desirable to drill the upper part of the well bore by the use of the surface casing as a drilling string, which will remain and be cemented in the hole after the latter has been drill d to the desired depth.

Thereafter, drilling of the hole through the surface casing can be continued, H

An object of the present invention is to provide improved drilling apparatus rotatable by casing to be cemented in the bore hole produced, in which the lower portion or shoe of the casing has cutters thereon to drill the outer portion of the bore hole, and in which the inner portion of the hole isdrihed by 'a bit structure rotatable by the casing and which is retrievable through the casing so as leave the passage through the casing unobstructed.

Another object of the invention isto provide drilling apparatus adapted for rotation by casing, in which the bit structure can be retrieved through the casing whenever desired, and the same, another or modified structure subsequently lowered through the casing to be coupled thereto for continued drilling of thewell bore.

A further object of the invention is to provide an apparatus adapted to be lowered and retrieved through well casing and embodying improved means for releasably coupling the apparatus to the casing so that it can be rotated thereby, the drilling weight from the casing being imposed upon the apparatus or transmitted through the apparatus to a rotatable drill bit attached thereto.

This invention possesses many other advantages, and has other objects which may be made more clearly ap parent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limitnig'sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings: FIGURE 1 is a longitudinal section through an appanatus embodying the invention disposed in a well bore, with the inner portion of the apparatus latched or coupled to the casing shoe or outer portion of the apparatus;

FIG. 2 is a partial longitudinal section similar to FIG. 1 illustrating the inner portion of the apparatus released from the outer portion;

FIG. 3 is a cross-section taken along the line 3-3 on FIG. 2. 7,

It is desired to drill a bore hole'A, as in a formation underlying a body of water, by rotating a string of casing lO ice its upper end for threaded attachment to the adjacent end of the casing section B thereabove. Attached to the lower portion of the shoe 1% in any suitable manner, as by Welding, are circumferentially spaced cutter structures 12 which may include arms 13 rotatably carrying toothed roller cutters 14 adapted to roll around the outer portion 15 of the bottom 16 of the hole A, drilling such outer portion from the wall 17 of the hole substantially to the inside diameter 18 of the casing shoe. Although two cutters 14 are disclosed, it is to be understood that a greator number of circumfer'entially spaced cutters can be used, and ordinarily would be used, where the diameter of the well bore A is relatively large.

The inner or central portion 19 of the hole, which is theportion extending inwardly approximatelyfrom the inside diameter 18 of the casing shoe 1%, is drilled by a rotary drill bit 29 of any suitable type secured'to a coupling structure 21 releasably attachable to the shoe ill of the casing string B, and through which the inner drill bit 2% can be rotated, and through which drilling weight can be imposed on the inner drill bit 25). The coupling structure 21 includes a body 22 'adapted to be lowered down the casing string B and to be received within the casing or drive shoe 10. Downward movement of the body 22 within the shoe is limited by engagement of an upper stop flange 23 of the body with an upwardly facing supporting and stop shoulder 24- in the upper portion of the drive shoe. The lower portion of the body 22 may be constituted as a threaded box 25 adapted to threadedly receive the usual pin 26 at the upper end of the drill bit body 27, the drill bit shown in the drawings including cutters 28, such as cutters or" the toothed roller type, adapted to operate upon the central portion 19 of the bottom of the hole.

The coupling body 22 is adapted to be releasably locked to the casing shoe 10 by a plurality of circumferentially spaced coupling or latch members 29 disposed in a body slot 30 and pivotally mounted on hinge pins 31 extending across the slot and suitably secured to the body. Each coupling member 29 has a leg portion 32 depending from its hinge pin 31 and terminating in an outwardly directed lock dog or lug 33. Each leg portion also has an inwardly directed expander or lock portion 34. When the coupling body 22 is disposed in the drive shoe-10 with its stop flange 23 engaging the stop shoulder 24, the lock dogs 33 are positionable into recesses, slots or sockets 35 in the drive shoe 10 which open into the interior of theJatter. Each recess 35 is defined by opposed parallel side walls 36 spaced apart the same distance as the opposed sides 37 of a dog and by a top wall 38 adapted to bear against the upper end 39 of a dog when the latter is disposed in the recess.

The coupling members 2? can occupy a retracted position substantially entirely within the peripheral confines of the body 22, and may be expanded outwardly to shift their dogs 33into the shoe recesses 35. As shown, the body 22 has a central longitudinal passage 40 extending therethrough slidably receiving a tubular mandrel or plunger 41. A socket head 42 may be threaded, or otherwise suitably secured, to the upper end of this plunger 41 above the body 22, the lower end of an upper section 43 of the plunger being threaded into an expander and lock member 44, which, in turn, is threaded onto the upper end ofa lower mandrel or plunger section 45 slidable in the body passage 40 below the body slot 3% In effect, the upper socket 4-2, upper and lower wardly in the body. Leaka e of'fluid along the mandrel is prevented by a suitable side seal ring 4'7, such as a.

rubber or rubber-like C-ring, disposed in an internal groove 48 in the body and sealingly engaging the periphery of the upper mandrel section Another side seal ring 49, such as a rubber or rubber-like O-ring, is also disposed in an internal groove 59in the lower portion of the body below the body slot 3% for sealingly engaging the periphery of the lower mandrel section '45. The upper portion of the drive shoe it? also has an internal groove 51 containing a suitableside seal ring 52, such as a rubber or rubber-like O-ring, adapted to seal against the periphery of the body 22. Because of the seal arrangements, fluid pumped down throughthe casing string will pass through the mandrel passageSS and its orifice 46 into the lower portion 54 of the body passage 40, continuing on through the central passage 55 of the drill bit body 27, and through its passages or nozzles 56 on to the cutters 28 and the bottom 16 of the well bore A for the purpose of flushing t e cuttings fromthc bottom of the hole and conveying them upwardly around the casing B to the top of the hole. 7 I

Initially, the coupling members 2 are disposed. in a greases the coupling member legs with the inner wall 18 of the casing shoe.

For the purpose of facilitating entry of the dogs 33 into the casing shoe recesses 35, the casing shoe may be provided with an internal relief groove 66 in the plane of its recesses .35, so that the dogs 33 will expand outwardly into such groove when disaligncd; with respect to theshoe recesses 35, preventing upward movement of the body 22 in the shoe it 7 The dogs will then slide relatively around such groove 66 as the casing string B and shoe 1% are rotated until the recesses 35 are brought into full alignment with t to dogs 33, the latter than snapping outwardly into'the recesses and coupling the body 22 to the drive shoe.

Drilling can now proceed by rotating the casing string is and imposing the requiredamount of drilling Weight on the cutters -24, 2S, and also by pumping drilling mud, or other drilling fluid, downwardly th ough the casing retracted position substantially entirely Witmn t to confines of the body 22. At this time, the plunger or mandrel 41 is disposed in its upper position, asshown in FIG. 2. The inner portion 21 of the apparatus disclosed may be lowered down through the casing string B by means" of a suitable spear 6% received within the mandrel socket 42 on a wire line (not shown), or it may be pumped down the'casing string, the coupling dogs 33 sliding along the wal-lof the casing string, with the mandrel remaining in its upper position. Downward movement of the coupling device 21 and bit 20 continues until' they enter the casing shoe 19 and the stop fimge 23 engages the stop shoulder 24 at the upper portion of theshoe. At this time, the lock dogs 33- are disposed in the plane of the shoe recesses or slots The parts are so proportioned that the inner drill bit member 2% is then disposed for operation on the bottom 16 of the hole, its it cutters 28 being located in substantially the same horizontal plane as the outer cutters 14 whose supporting arms 13 are secured or fixed to the lower portion of the drive shoe 10.

If the spear has been used for lowering the coupling apparatus 21 and bit 20 through the well casing, it is released from the socket 42 and removed from the Well casing B, after which fluid-is pumped down through the casing string, flowing into and through the mandrel 41. In view of the orifice 46 through the mandrel, or, for that matter, in view of the restricted area through the. central mandrel passage 53, a fluid back pressure is built up above the mandrel, urging it downwardly in the body passage 4t its expander 44 engaging the expander surfaces ll on the inner projections 34 of the coupling members 29 and shifting these members outwardly, their dogs 33 moving into the casing shoe recesses 35. If the coupling dogs 33 are out of alignment with the casing shoe recesses 35, the casing string. B may be rotated slowly, the inner cutters 23 engaging the bottom 16 of the hole and resisting turning of the body 22 until the recesses 35 are laterally aligned with the coupling dogs 33, which will then snap into the recesses, the plunger 41 then moving down within the body 22 to the extent at which its expander member 44 engages a guide 2 extending across the body slot 30 and fixed to the body, and through which the mandrel 41 is slidable. At this time, outer holding surfaces 63' on the expander are disposed behind companion holding surfaces 64 on the inwardly projecting portions 34 of the coupling members 29, for the purpose of positively holding the coupling member dogs 33 outwardly and fully'within the shoe recesses 35. The extent of outward movement of the coupling members 29 may be limited, ifdesired, by engagement of the outer. longitudinal surfaces 65 of into the central drill bit 2%, discharging from its passages or nozzles 56 toward the bottom 16.01: the hole, for the urpose of carryingthe cuttings away from this region and conveying them around the exterior of the casing String B to the top of the well bore. Drilling weight is imposed directly upon the outer cutters 14, which are cutting theiouter portion 15 of the hole. Drilling weight is also being transmitted from the upper end walls 38 of the recesses 35 to the upper ends 39 of the lugs 33, and through the coupling members 29 and binge pins 31 to the body 22 of the coupling apparatus 21, from where the drilling weight is transmitted through the inner drill bit body 27 to the inner cutters 28. 1

Drilling will proceed until the required length of'hole A has been produced, at which point it is usually desired to cement the casing B in place. The coupling apparatus 21 and inner drill bit 263 can then be removed through the casing to the top of the hole. A suitable spear 60 is lowered on a wire line (not shown), or the'like, through the casing, the spear entering and becoming coupled to the socket 42 at the upper end of the mandrel 41. The taking of an upward pull on the wire line and spear will elevate the mandrel 4-1 within the body 22, shifting the expander 44 above the inner portions 34 of the coupling or latch members 29, a shoulder on the mandrel engaging the upper inner arms 71 of the coupling members and shifting such arms 71 inwardly and swinging the coupling members 29 about their hinge pins31 to retract the dogs 33 fully from the shoe recesses 35 and the groove 66, and completely within the confines of the casing shoe 10. The wire line and spear can now be elevated, carrying the mandrel 41 upwardly with it, together with the coupling body'22, latch members 29, and the drill bit 20, all

of these parts being removed through the casing B to the top thereof for removal.

The passage through the casing is now unobstructed. A suitable charge of cement slurry can now be pumped down the casing string B in a known'manner forupward passage through the annulus around the casing, in order to cement .the casing in place. A drilling operation through this string of casing B, which may be the surface casing, can now take place in any known manner, as by lowering a drill bit on a string of drill pipe (not shown) through the casing for action upon the bottom of the hole. The size of the hole being drilled will ordinarily be slightly less than the inside diameter of the casing shoe 10. Inthe event that the inner cutters 28 become dull before the hole A has been drilled to the desired depth through use of the casing as a drilling string, the coupling device '21' and the inner bit 20 attached thereto can be released from the drive shoe 10 and removed through the casing B, and another drill bit secured to the 'lowerend of the coupling body 22, this combination of apparatus then being lowered through the casing string B into the casing shoe 1%, the pumps at the top of the hole being started to develop sufficient pressure to shift the mandrel 41 down- "wardly for the purpose of expanding the dogs 33 into the I recesses 35 and again coupling the apparatus 21 to the the wellbore A has been completed to the desired depth,

the inner bit-20 and coupling structure 21 can be removed from the well casing B in the manner described above, and

another type of drill bit and coupling structure lowered through tthe casing string. Such cutter and coupling structure can include an expandible type of bit, the upper end of which would be threaded to the box 25 of the body 22 of the coupling device 21, the lower end of which would be secured to a drill bit for cutting the central part 19 of the hole. The expandible cutters would have a range of expansion todrill the' same diameter hole A and operate upon substantially the same annulus 15 of the bottom 16 of-the hole as the casing cutters 14 .dis closed in FIG. 1.

The combination of apparatus just referred to is disclosed in FIG. in my copendingapplication for Retrievable Subsurface Well BoreApparatus, SeriaLNof 841,370, filed September 21, 1959. After the wellbore A has been drilled to the desired depth through the use of such apparatus, it can be released from the casing shoe 10 and elevated through the casing string B to the 'top thereof, after which the casing string can be cemented in place I claim: a V a 1. In apparatus adapted for operation in a well bore: a tubular member adapted to form part of a string of pipe to belowered in the-well bore and having a substantially smaller outside diameter than the diameter of the well bore, said member having first stop means therein; a coupling body adapted to move through the string of pipe into said tubular member, said body having second stop means engaging said other stop means to limit downi ward movement of said body in said tubular member;

said tubular member having an inner circumferential groove intermediate its length and circumferentially spaced recesses laterally outwardly of and opening radially into said groove; coupling members mounted on said body for lateral movement with respect thereto and disposed in the horizontal plane of said groove and recesses when said second stop means engages said first stop means; a tubular mandrel slidably mounted in said body and engageable with said coupling members for expanding said coupling members into said groove and recesses, whereby rotation of said tubular member is transmitted through said coupling members to said body; outer cutter means secured to the lower end of said tubular member to cut the outer portion of the bottom of the bore hole; the lower portion of said body having a connection for attachment thereto of a drill bit to cut the inner portion of the bottom of the bore hole; and means for retracting said coupling members from said recesses and groove to enable said a body to be elevated from said tubular member and through the pipe to the top of the well bore to leave an unobstructed passagev through the pipe and its tubular member. 7

2. In apparatus adapted for operation in a well bore: a tubular member adapted to form part of a string of pipe to be lowered in the well bore and having a substantially smaller outside diameter than the diameter of the well bore, said member having first stop means therein; a coupling body adapted to move through the string of pipe into said tubular member, said body having second stop means engaging said other stop means to limit downward movement of said body in said tubular member; said tubular member having an inner circumferential groove intermediate its length and circumferentially spaced recesses laterallly outwardly of and opening radially into ,said groove; coupling members mounted on said body for lateral movement with respect thereto and disposed bodying hydraulically operable means responsive to the pressure of drilling fluid pumped down thestring of pipe for shifting said mandrel downwardly in, said body to expand said coupling members; outer outter means secured to the lowertend of said tubular member to cut the'out er portion of the bottom of the bore hole laterally outwardly 'of the inside diameter of the tubular member; the lower portion of said body having a connection for attachment thereto of a drill bit to cut the inner portionof the bottom of the bore hole laterally inwardly of theinside diameter of the tubular member; and means for retracting said coupling members from said recesses and groove to enable said body to be elevated from said tubular member and through the pipe to the top of the well bore 'to leave an unobstructed passage through the pipe and its tubular member. r

3; In apparatus adapted foroperation in a well bore: a tubular member adapted to form part of a striug of pipeto be lowered in the well bore and having a substantially smaller outside diameter than the diameter of the well bore, said member having first stop means therein; a coupling body adapted to move through the string of pipe into'said tubular member, said body having second stop means engaging said other stop means to limit downward movement of said body in said tubular member; said tubular member having a recess substantially above its lower end and opening into its interior, said recess including a side wall of said tubular member; a coupling member mounted on said body for lateral movement with respect thereto and disposed in the horizontal plane of said recess when said second stop means engages said first stop means; a tubular mandrel slidably mounted in said body and engageable with said coupling member for expanding said coupling member into said recess when said second stop means engages said first stop means, whereby rotation of said tubular member is transmitted through its recess side wall to said coupling member and to said body; outer cutter means secured to the lower end of said tubular member to cut the outer portion of the bottom of the bore hole; the lower portion of said body having a connection for attachment thereto of a drill bit to cut the inner portion of the bottom of the bore hole; said tubular mandrel extending into said lower portion of said body in leakproof relation thereto to feed fluid into said lower portion and through said connection into the drill bit when attached thereto; and means for retracting said coupling member from said recess to enable said body to be elev vated from said tubular member and through the pipe to the top of the well bore to leave an unobstructed passage through the pipe and its tubular member. I

4. In apparatus adapted for operation in a well bore: a tubular member adapted to form part of a string of pipe to be lowered in the well bore and having a substantially smaller outside diameter than the diameter of the well bore, said member having a first stop means therein; a coupling body adapted to move through the string of. pipe into said tubular member, said body having second stop means engaging said other stop means to limit downward movement of said body in said tubular member; said tubular member having a recess substantially above its a second stop means engages said first stop means, whereby rotation of said tubularmember is transmitted through its recess side Wall to said coupling member and to said body; said mandrel embodying hydraulically operable means responsive to the pressure of drilling fluid pumped down thestring of pipe for shifting said mandrel down- Wardly in said "body to expand said'coupling member into said recess; cutter means secured to the lower] end of said tubular member to cut the outer portion of the bottom' of the bore hole outwardly of the inside diameterf of the tubular member'; the lower portion of said'b'ody having .a' connection for attachment thereto, offa' drill bit j-to cut the inncrportionof the bottom of the bore hole laterally inwardly of the insidediameter of the tubular member; said tubular mandrel extending into saidllower' portion of said body in leakproof relation-thereto'to feed fluid into said lower portion and-through said'c onnectio'n -into' the drill bit when attached thereto; and means for retracting said coupling member from said'recessto enable s'aid body to be'elevated from said tubular member andthrougli the pipe to, the top, of the Well bore to leave'an unobstructed passage through the pipe and its tubular member.

intermediate its length and circumferentially spaced recesses laterally outwardly of and opening radially into "said groove; coupling members mounted on said body for lateral movement with respect thereto. and dispose in the horizontal plane of said groove and recesses when said second stop means engages said first stop means; a tubular mandrel slidably mounted in said bodyandengage-able with said coupling members for expanding said coupling members into said groove and recesses; whereby rotation of said tubular member is transmittedthrough said coupling members to said body; said mandrel embodying hydraulically operable means responsive'to the pres sure of drilling fluid pumped down the string'of pipefor shifting said mandrel downwardly insaid body to-expand said coupling members; outer cutter means'secured to the lower end of said tubular member'to cut the outer portion of the bottom of the borehole laterally outwardly-' of theinside diameter of the tubular member; the lower portion of said body, having a connection for attachment-thereto of a drill bit to cut the inner-portion er the bottom of I the bore hole laterallyinwardly-of the inside diameter of.

the tubularmember; said-tubular mandrel extending into saidlower portion of said body in leakproof relation thereto to feed fluid into saidlower portion and through said connection into the drill bit when attached thereto; and

means for retracting said coupling members fromsaid recesses and groove to enable said body to be elevated from'said tubular member and through the pipe to the top-of the well'bere to leave an unobstructed pass-age through the pipe and its tubular member.

' Referenees Cited in the fileof this patent v UNITED sTATEs PATENTS Ruby June 8, 1915 1,671,136 Stokes May 29, 1928 2,220,554 Straatman Nov. 5, 1940 2,251,679 Kinnear Aug. 5, 1941 3,050,142 Kammerer Aug. 21, 1962 

1. IN APPARATUS ADAPTED FOR OPERATION IN A WELL BORE: A TUBULAR MEMBER ADAPTED TO FORM PART OF A STRING OF PIPE TO BE LOWERED IN THE WELL BORE AND HAVING A SUBSTANTIALLY SMALLER OUTSIDE DIAMETER THAN THE DIAMETER OF THE WELL BORE, SAID MEMBER HAVING FIRST STOP MEANS THEREIN: A COUPLING BODY ADAPTED TO MOVE THROUGH THE STRING OF PIPE INTO SAID TUBULAR MEMBER, SAID BODY HAVING SECOND STOP MEANS ENGAGING SAID OTHER STOP MEANS TO LIMIT DOWNWARD MOVEMENT OF SAID BODY IN SAID TUBULAR MEMBER; SAID TUBULAR MEMBER HAVING AN INNER CIRCUMFERENTIAL GROOVE INTERMEDIATE ITS LENGTH AND CIRCUMFEREITIALLY SPACED RECESSES LATERALLY OUTWARDLY OF AND OPENING RADIALLY INTO SAID GROOVE; COUPLING MEMBERS MOUNTED ON SAID BODY FOR LATERAL MOVEMENT WITH RESPECT THERETO AND DISPOSED IN THE HORIZONTAL PLANE OF SAID GROOVE AND RECESSES WHEN SAID SECOND STOP MEANS ENGAGES SAID FIRST STOP MEANS; A TUBULAR MANDREL SLIDABLY MOUNTED IN SAID BODY AND ENGAGEABLE WITH SAID COUPLING MEMBERS FOR EXPANDING SAID COUPLING MEMBERS INTO SAID GROOVE AND RECESSES, WHEREBY ROTATION OF SAID TUBULAR MEMBER IS TRANSMITTED THROUGH SAID COUPLING MEMBERS TO SAID BODY; OUTER CUTTER MEANS SECURED TO THE LOWER END OF SAID TUBULAR MEMBER TO CUT THE OUTER PORTION OF THE BOTTOM OF THE BORE HOLE; THE LOWER PORTION OF SAID BODY HAVING A CONNECTION FOR ATTACHMENT THERETO OF A DRILL BIT TO CUT THE INNER PORTION OF THE BOTTOM OF THE BORE HOLE; AND MEANS FOR RETRACTING SAID COUPLING MEMBERS FROM SAID RECESSES AND GROOVE TO ENABLE SAID BODY TO BE ELEVATED FROM SAID TUBULAR MEMBER AND THROUGH THE PIPE TO THE TOP OF THE WELL BORE TO LEAVE AN UNOBSTRUCTED PASSAGE THROUGH THE PIPE AND ITS TUBULAR MEMBER. 